eigenvalues

Yeah. This functionality is in Mx 1.0 using the functions \eval() and \evec(). We should get around to implementing them in OpenMx. We will probably implement a subset of the R function eigen() that does not use either named arguments or boolean arguments, since OpenMx does not support either of these constructs. I think we'll write one function in R that does

Re(eigen(foo, only.values = TRUE)$values)   # omxEigenRealVal?

and another that does

Re(eigen(foo)$vectors)   # omxEigenRealVec? 

Dear all,
just to make sure I understand things correctly: There is currently no way to compute a matrix exponential in openMx, right? In Mx this was possible via the eval() and evec() functions, but both are not (yet) implemented in openMx, right? Are you planning to implement these functions soon? Thank you so much for your help!

Ah. So each matrix operator or function that is supported by OpenMx is implemented twice. One of these implementations is the operator/function as supported in the R language. So the sin() function is the R primitive for the trigonometric function. The implementation of the R primitive is available in the R source code. But each matrix operator or function is also implemented by the OpenMx developers in C. This is because we use a FORTRAN numeric optimizer and compute the algebra expression in C without any callbacks to the R interpreter. To see our implementation of the matrix functions you can look at http://openmx.psyc.virginia.edu/repoview/1/trunk/src/omxAlgebraFunctions.c. To see the mapping of names look at http://openmx.psyc.virginia.edu/repoview/1/trunk/data/omxSymbolTable.tab. The 3rd column is the name in R, and the 5th column is the function name in C.

The OpenMx functions are named eigenval, eigenvec, ieigenval, and ieigenvec. See

?eigenval

.